This no lucrative moonlight options for pathologists in trainee aside from Biotech consulting, which of course not everyone is equipped to do.
Im very skeptical of the lucrative ME office work because most states require at least BC in Pathology if not BE/BC in Forensics as well.
If moonlighting is what you are after, Surgery subspec are FAR and AWAY the best. Covering SICU, CCU etc. can net $100,000/year+ as a surg resident on a research rotation with the time and energy to "ball it out."